description

In order to develop smart sensor networks, the electronic sensors must be low-cost and flexible to enable widespread distribution. To meet those criteria, we have developed organic integrated circuits fabricated by all-additive solution processes. One of the prototypes we have demonstrated is a temperature sensor tag consisting of a printed thermistor bridge, a threshold control circuit, and non-volatile memories. The threshold control circuit is based on inkjet printed complementary transistors, and the non-volatile memories are capacitors with ferroelectric polymer dielectric. When the thermistor temperature exceeds a pre-set threshold (above 35 degrees C or below 4 degrees C), the control circuit is triggered to generate a pulse to write into the memory. This temperature sensor tag is self-contained and will be applicable to packaging or environmental monitoring applications. In addition to demonstrating the tag performance, we will discuss our approach to tackle the challenges of device variations and stability in printed devices. We will show some design rules for printed sensor platforms, in order to improve the reliability of the fabrication processes and accelerate the development of printed electronics.